Shelter having a stressed frame with a flexible sheathing thereon

ABSTRACT

A skeleton-frame having a substantially arcuate shaped crosssection and a shelter having such a frame covered by a relatively thin flexible sheathing is fabricated from a first series of flexible, longitudinally substantially equally spaced parallel obliquely extending arched rods and a second series of oppositely extending similarly spaced oblique arched rods crossing the rods of the first series to define a network of regularly spaced support members secured at their ends under tension and fastened together adjacent to cross-over points against relative movement. The resulting skeleton-frame of stressed members is adapted to respond as a unit to the application of an applied force or load to the surface of the shelter.

1 July 1,1975

1 1 SHELTER HAVING A STRESSED FRAME WITH A FLEXIBLE SHEATHING THEREON I76] Inventor: William N. Spray. RD. 1. Fredericktown. Pa. 15333 122] Filed: June 4, 1973 1211 Appl. No: 366.509

152] U.S. Cl. 52/63; 52/80; 52/86; 135/3 R; 52/143. 52/644 [5]] Int. Cl 1304b 1/347 158] Field of Search H 52/63. 86. 648. 80. 81, 52/143; 135/3 R. I R. 4 R; 403/73. 385. 389

[56] References Cited UNITED STATES PATENTS 2.351.858 6/1944 lngalls 403/389 2.690.185 9/1954 Pomykala 52/80 X 2.711.180 6/1955 Sims ct al 135/3 R 2.716.993 9/1955 Codrick 52/81 X 2.752.868 7/1956 Blumfield 1. 52/86 3.100.555 8/1963 Ashton 1 A 403/172 3.233.617 2/1966 Stern t. 135/3 R X 3.480.060 11/1969 Sheldon 403/389 3.483.879 12/1969 Oehmsenn 52/86 X 3.525.290 8/1970 Pelsue 135/1 R 3.690.078 9/1972 Maynard 135]] X 3.749.107 7/1973 Laberge 135/1 R 3.765.134 Ill/I973 Gilchrist 52/86 X FOREIGN PATENTS OR APPLICATlONS 826.525 1/1938 France 403/385 165.050 2/1953 Australia 52/80 353.610 7/1931 United Kingdommnnw. 52/86 Primary E.t'umt'mr'--Frllnk L. Abbott Assistant E.t'umir1erLes1ie A. Braun Attorney. Agent. or FirmUpchurch. Clelle W.

[57] ABSTRACT A skeletomframe having a substantially arcuate shaped cross-section and a shelter having such a frame covered by a relatively thin flexible sheathing is fabricated from a first series of flexible. longitudinally substantially equally spaced parallel obliquely extending arched rods and a second series of oppositely extending similarly spaced oblique arched rods crossing the rods of the first series to define a network of regularly spaced support members secured at their ends under tension and fastened together adjacent to cross'over points against relative movement. The resulting skeleton-frame of stressed members is adapted to respond as a unit to the application of an applied force or load to the surface of the shelter.

18 Claims. 18 Drawing Figures SHEET u m Y FIG.7

SHELTER HAVING A STRESSED FRAME WITH A FLEXIBLE SHEATHING THEREON This invention relates generally to a skeleton-frame and sheathing shelter having a generally semicylindrical top of improved stability and adapted to be assembled and disassembled quickly and easily without any special mechanical skill or knowledge.

Modular skeleton-frame buildings have been disclosed before. Such structures usually have a tubular steel frame covered with a sheathing of plastic, foil, fabric or the like. One such structure is disclosed. for example, in US. Pat. No. 3,690,078. The disclosed structure has the disadvantage that it requires a large number of tubular cross-members to support the rods used to impart the semi-cylindrical shape to the structure. Other skeleton-frame type structures covered with a limp sheathing have been proposed but all of them require a substantially large number of structural members for the arcuate shaped frame and many of them cannot be disassembled quickly and easily by a relatively unskilled worker.

It is therefore an object of this invention to provide a modular skeleton-frame which can be assembled or disassembled quickly even by an unskilled person and having a generally semicylindrical shape of improved strength and stability. Another object of the invention is to provide a relatively inexpensive shelter adapted to be used for a temporary or permanent storage which is relatively inexpensive and is adapted to be assembled or disassembled quickly at the location where it is to be used. Still another object of the invention is to provide a skeleton-frame and sheathing structure having a generally semicylindrical top fabricated from structural members under tension and adapted to resist an applied force or load without substantial permanent distortion. A still further object of the invention is to provide a generally semi-cylindrical skeletonframe structure for a shelter having crossed regularly spaced arched stressed rods removably secured to side rails and having improved resistance to distortion under an applied load or force.

Other objects will become apparent from the following description with reference to the accompanying drawing wherein:

FIG. I is a perspective view of one embodiment of the modular shelter of the invention with a portion of the sheathing broken away to expose the generally semi-cylindrical skeleton-frame which supports the sheathing;

FIG. 2 is a crosssection of the modular skeletonframe structure of FIG. 1 provided with one-type of reinforcement for the skeleton-frame and with means for attaching the structure to the ground;

FIG. 3 is a fragmentary plan view of two of the modular structures of FIG. 1 with sheathing partially broken away to expose the skeleton-frames of the two structures where they are attached together in tandem;

FIG. 4 is an enlarged fragmentary perspective view showing one embodiment of the side rails taken along the line 4-4 of FIG. 3',

FIG. 5 is an enlarged fragmentary exploded perspective view of the side rails of a skeleton-frame illustrating one embodiment ofa means for connecting the side rail to an end rail;

FIG. 6 is a fragmentary side elevation taken along the line 6-6 of FIG. 3 showing one embodiment of a clamp for securing rods together adjacent to a crossover point;

FIG. 7 is a plan view of one-half ofthe clamp of FIG. 6 prior to installation;

FIG. 8 illustrates the clamp of FIG. 7 installed between the line 88 of FIG. 3;

FIG. 9 is a section taken along the line 99 of FIG.

FIGS. [0 and 11 are an end view and a plan view. respectively, of an alternate embodiment of a clamp for securing stressed arched rods of the skeleton-frame together at their cross-over points;

FIG. 12 is a fragmentary side elevation showing the clamp of FIGS. 10 and II installed at a cross-over point;

FIG. 13 is a fragmentary perspective view of a clamp and side rail assembly illustrating a means for attaching the sheathing to the side rails;

FIG. I4 is a fragmentary section showing a means for securing the sheathing to the end of a modular skeleton-frame;

FIG. 15 is a fragmentary sectional view of one means for securing the sheathings across the juncture of two modular skeletonframes connected together in tandem;

FIG. 16 is an illustration in a fragmentary sectional view of an alternate means for securing the sheathing across the juncture of two modular skeleton-frames connected together in tandem;

FIG. 17 illustrates in a side elevation an embodiment of the invention in one possible position to be towed from one location to another; and

FIG. 18 is a fragmentary plan view of a preferred embodiment of the invention.

The foregoing objects and others are accomplished in accordance with this invention, generally speaking. by providing a shelter having a generally semi-cylindrical skeletonframe having a first series of equally longitudinally spaced, substantially parallel arched rods under tension attached adjacent their ends to laterally spaced side rails with one end of each rod being longitudinally spaced from the opposite end thereof and a second se ries of arched rods spaced longitudinally in parallel relationship from each other a distance equal to the spacing between the rods of the first series and secured to the laterally spaced side rails with one end of each rod longitudinally spaced from the other end thereof a distance equal to the distance between ends of the rods of the first series but in a direction opposite from the spacing between the ends of the rods of the first series whereby rods of one series cross the rods of the other series at least once between the side rails and preferably more than once when additional contraint is required. The length of all of the rods in the two series is substantially equal and greater than the spacing between the side rails which spacing is maintained substantially equal from one end to the other. The rods of the two series of the skeletonframe are spring steel, fiberglass or similar material which can be deflected substantially from normal without becoming permanently deformed.

The term generally semi-cylindrical skeletonframe is used herein to describe a structure which has a substantially rectangular cross-section in a longitudinal vertical median plane therethrough and has a crosssection in a plane perpendicular to the longitudinal plane which is arched to form an arc of a circle of up to 180. The arched rods of each series may be solid in cross-section or tubular and may be bent into any are of a circle of up to 180 depending upon the length of the rod. the space between side rails and the height desired for the generally semi-cylindrical portion of the shelterv The rods of two series which cross each other are substantially equally spaced but series of different spacings may be joined end to end on the same side rails.

The end of the skeleton-frame is completed by providing an arched shaped rod under tension having its two ends attached to side rails directly opposite each other and a rod which is parallel on one side of the gen erally semi-cylindrical shaped structure to the rods of one series and bent to be parallel to the rods of the second series on the other side to complete a regular net work of spaced crossed rods extending as arcs along an interrupted helical path and enclosing repeating spaces having generally the shape of an oblique parallelogram. Any weight or other external force exerted against a rod tends to distort the nominal parallelogram and each side of the parallelogram must compensate for any deflection in the other three sides. Adjacent ends ofa rod of one series and a rod of the other series may be deliberately secured to a side rail out of the normal arcuate lines of the rods to create opposite tensions in each rod of the pair. This creates opposing tensions in each of the parallelograms of the row thereof which is adjacent to a rail. These tensions are transmitted through the de flection of each rod as it passes out of the parallelogram in which the stress originated. The skeletonframe can be constructed as a modular structure which may be connected to a similar structure in tandem, if desired. The overall surface of the skeleton-frame exposed to the sheathing is substantially smooth since the arched rods are equal in length and the spacing between the side rails is equal from one end to the other.

The rods of one series must be clamped or otherwise secured adjacent to cross-over points to rods of the other series. The rods tend to deflect from their normal path when clamped together so that the walls of the parallelogram are distorted and the segment of the rod between two clamped cross-over points is stressed or under tension. With such a construction, any load applied at any point to the skeletonframe is transferred from rod to rod and is thus supported by the entire assembly as a unit. A protective sheathing may be removably secured to the skeleton-frame such as by clamping the sheathing along its edges to the side rail and rods at the end of the frame. The sheath also acts to exert force on each rod to partially constrain it from bowing above the semi-cylindrical surface of the whole structure. This constraint adds to the strength and stability of the whole structure. The base or side rails of the skeleton-frame may be supported above the ground and sheathing panels may be hung from the rails to enclose the sides of the shelter. The ends of the generally semi-cylindrical structure may be left open or they may be closed with an end panel of sheathing clamped or otherwise secured to members of the skeleton-frame.

The invention provides clamps adapted to be used for securing the arched rods ofthe skeleton-frame together at cross-over points. One particularly advantageous clamp is formed by bending a metal band having longitudinally spaced parallel semi-cylindrically shaped grooves extending across the band. The grooves are arcuate shaped with a wall usually forming in crosssection an arc of less than and having a radius which is about equal to the radius of rods to be clamped together. If the clamp is made from spring steel. the crosssection of the groove may be more than 180. The clamp is bent 180 midway between its two ends until one groove crosses the other. The longitudinal axis of one groove is inclined at an angle equal to the inclination of the rods of one series of a skeleton-frame and the longitudinal axis of the other groove is inclined at an angle equal to the inclination of the rods ofthe other series. The ends of the band may be rolled and notched to form an interlocking means for securing the two ends together.

Referring now to the drawing, one embodiment of a shelter is illustrated in FIG. 1. A plurality of substan tially equally spaced spring steel rods A have one end thereof removably fixed to a side rail 10 and the other end removably fixed to side rail 11. Rods A are of equal length and of greater length than the distance between rails 10 and 11 so they are arched upwardly therebetween. ln one embodiment. rods A are spaced longitudinally along rail 10 about three feet apart with rod A being secured to rail 10 adjacent to one end of the rail 10. Each rod A is secured to rail 11 at a point longitudinally spaced about 6 feet from the point where it is secured to rail 10 so that the angle is an acute angle and the series of rods resembles somewhat less than a onehalf longitudinal section of a helix.

Each rod B ofa second series of spring steel rods has an end removably fixed to rail 10 and an opposite end removably fixed to rail 11. The spacing between rods B is substantially equal to the spacing between rods A with the ends ofa rod A and a rod B lying adjacent each other. That end of rod B attached to rail 11 is spaced longitudinally from the end attached to rail 10 a distance substantially equal to the longitudinal spacing between the ends of rods A. However, the spacing between the ends of a rod B is in the opposite direction from that between the ends of rod A so that rod A crosses three rods B in the embodiment illustrated in FIG. 1 and the resulting structure has the configuration of somewhat less than a one-halflongitudinal section of oppositely wound helices. The angle enclosed between rod 8 and rail 11 is an acute angle. The length of each of rods B is equal to the length of each rod A so they arch obliquely upwardly to form an arc of the same radius as the arcs formed by rods A.

A spring steel rod C is arched between each end of rail 10 to the opposite end of rail 11 and removably fixed thereto to terminate the modular skeleton-frame. The length of rod C is such that it forms an are equal in radius to that of the generally semi-cylindrical frame. A spring steel rod D is removably secured at one end to rail 10 adjacent to the second rod A moving from left to right as shown in FIG. 1. The opposite end of rod D is removably fixed to rail 11 adjacent to the second rod B moving from left to right as shown in FIG. 1. Rod D is clamped at its midpoint to rod C and is thus bent as shown in FIG. 3 to complete the spacing pattern of the skeleton-frame 14. The cross-section of the rods may be varied depending upon the width to be spanned, the weight to be supported and the length each segment thereof between crossover points. For example, a rod 7/16 inch in diameter may be used to make a very acceptable structure having a 20 foot span.

Side rails 10 and 11 are maintained in spaced relationship by an end rail 12 removably secured thereto.

Side rails IO and II and end rail I2 may be disposed directly on the ground or at an elevated position above the ground. Side rails and Il may be secured to posts 13 or to other structures to fix the skeleton-frame against movement by the wind or other force. When the skeleton-frame is so secured. cnd rail I2 is not needed. Skeleton-frame 14 may be covered with a sheathing l5, and if. as illustrated in FIG. 1, side rails 10 and l] are supported above the ground. a vertically disposed sheathing 16 may be secured to side rails I0 and II and a vertically disposed end sheathing 17 may be secured to rod F to complete the enclosure.

A convenient means for attaching the skeleton-frame 14 to the ground or other foundation is illustrated in FIG. 2. Posts 13 are provided with vertically spaced brackets 18. Side rails I0 and 11 may be removably secured to any pair of brackets 18 after posts 13 have been driven in the ground depending upon the height desired for the shelter. The width of skirt l6 and the length of end panel 17 may be varied with the height of the brackets 18. The skeleton-frame may also be attached to any other adjacent structure, in lieu of any or all of the posts.

A clamp 19 at each cross-over point of rods A and B strengthens the skeleton-frame I4. Because all of rods A and B are secured together adjacent the cross-overs, the weight of any load or any force applied to any part of skeleton-frame I4 is spread over the entire skeletonframe 14. Rods A and B are under tension in their arched position and resist compression under any applied load. When any rod is forced into a deflected position it can return to its original position as soon as the applied force is removed without permanent damage or bending. even though the deflection may amount to several inches.

Skeleton-frame 14 may be strengthened. if desired. by providing reinforcing rods or tensile ties E illustrated in FIG. 2. One end of a rod or tensile tie E is removably fixed to rail I0, clamped to rod C at a point between rail 10 and the point where rods D and C are clamped together and then clamped at its other end to rod C on the opposite side of the point where rods D and C are clamped together. A second rod E is removably fixed to rail II and clamped to rod C on each side of the points where rods C and D are clamped together, as illustrated in FIG. 2. In an alternate embodiment, turnbuckles may be substituted for rods E. Such rods or tics can be used across any chord of the arc of the whole structure.

Two or more skeleton-frame structures 14 can be joined together in tandem to provide a longer semicylindrical structure. if desired. As illustrated in FIG. 3, the end of skeleton-frame 14 is modified when it is desired to have modular structures adapted to be joined in tandem. A spring steel rod F is arched between rails 10 and 11 substantially parallel to rod C and spaced longitudinally therefrom only a short distance. As shown in FIG. 3, a rod A is fixed to rail 10 between rods C and F and a rod B is fixed to rail 11 between rods C and F.

To join one skeleton-frame 14 to another, two skeletonframes I4 similar to the one of FIG. I are disposed end to end as shown in FIG. 3. Rods C, F and D of each unit are clamped together at substantially the midpoint of rod C between rails I0 and II. As illustrated best in FIG. 4, side rail 10 is two tubular members or pipes 10a and 10b disposed one above the other with spacer bars 20 welded at longitudinally spaced points therebetween. Three spaced holes are drilled in top tube 10a of rail I0 of each modular skeleton-frame 14. A sleeve 24 having holes 21, 22, 23. 25. 26 and 27 spaced to be aligned with holes in tube is slipped over the end of tube 10a of one skeleton-frame l4 and the end of tube 100 of a second skeleton-frame 14 is inserted in sleeve 24 until it abuts the end of tube 10a of the first skeleton-frame 14. The ends of the rods A. C and F of the first skeleton-frame 14 are disposed through holes 22, 23 and 21 in sleeve 24 and through the underlying holes through tube [0a with the ends of rods A. C and F disposed on tube I0b. as illustrated in FIG. 4. The rods A. C and F of the second skeleton-frame I4 are passed through holes 26, 25 and 27, respectively. and underlying holes through tube [0a with the ends of the rods A. C and F disposed on the surface of tube 10!). The ends of tubes 10b of the two structures abut each other as shown in FIG. 4. A second sleeve 24 is disposed over the ends of tubes 11a of rails II and rods B, C and F are inserted through the holes of the sleeve and tube 11a in the same way to join the two skeletonframe units together on the side having side rail I]. Two skeleton-frames l4 are then removably fixed together in tandem.

Those ends of a modular skeleton-frame I4 which are not secured to another skeleton-frame I4 may be provided with a cross-rail or end rail I2 as illustrated in FIGS. I and 5. Each end of rail I2 is bent until substantially perpendicular to the remainder thereof as illustrated in FIG. 5. A sleeve 24 is disposed over the end of tube 10a of side rail 10 and rods A, C. F are disposed through holes 22, 23 and 21 and underlying holes through tube 10a as described above with respect to FIG. 4. The end of end rail 12 is inserted in the remaining open end of sleeve 24 until the hole therein is aligned with a hole 25, 26 or 27. A pin or bolt 29 may then be inserted through one of the holes in the sleeve and hole 28 in the rail I2 thereby secured to side rail 10. The opposite end of rail 12 is secured in the same way to the end of rail II.

Since the arched rods A. B. C. D. E and F are spring steel they are stressed under tension and the ends thereof are constantly pressing against the wall of the holes through sleeve 24 and the rails 10a and Ila in an attempt to return to their normal straight lengths or to their normal greater radius. or to their normal smaller radius. Rods with a normal radius just equal to the radius of the assembled structure can be used but there is a loss of the deliberate tensioning of the rods at the point where they enter the side rails. and a weakening of the torque applied by the rails to the rods. The pressure of the rod against the wall of the hole in some embodiments is sufficient that clamping or other securing means is not required. However, clamping is contemplated for some embodiments. As shown in FIG. I, rods A and B are clamped together adjacent to each crossover. Also, as shown in FIG. 3, rods C. F and D may be clamped together. A clamp 29 suitable for fixing the rods together at all of these points is illustrated in FIGS. 6, 7, 8 and 9. As shown in FIG. 7, clamp 19 is formed from a metal band which may have two holes 29 and 290 near the ends thereof. One band is bent around rod A and another about rod B (FIG. 9). The distance between the centers of holes 29 and 29a is such that when the two bands of clamp 19 are installed about rods A and B with their holes 29 and 29a aligned as shown in FIGS. 6 and 9, there will always be space between the overlapping ends for further tightening by bolt 30. Clamp 19 is illustrated in FIG. 8 about a pair of rods A and B between tubes 10a and "lb to secure the ends of rods A and B.

Another clamp which may be used to advantage to removahly secure rods A and 8 together at cross-over points is illustrated in FIGS. I0, 11 and 12. As shown in FIGS. I and 1] a pair of spaced semi-cylindrical grooves 31 and 310 are formed in a metal band 32. The longitudinal axes of the grooves 31 and 31a are substantially equal to angles a and B at the intersection of rods A with rail 10 and rods B with rail 11. Band 32 is bent along line 33 about rods A and B at a cross-over point as illustrated in FIG. I2. Band 32 has a pair of rolled edges 34 and 34a with a notch 35 therebetween on one end and a rolled edge 36 on the other end which intermesh as shown in FIG. 12 when band 32 is bent around rods A and B. A pin 37 is inserted through the intermeshing rolled portions 34, 36 and 34a to secure the clamp in place. The walls of grooves 31 and 31a are arcs of a circle of less than 180.

The generally semi-cylindrical surface of skeletonframe 14 may be covered with any suitable flexible sheathing I such as a polyethylene film, a polyvinyl chloride film. an aluminum sheet, a steel sheet, fabric or the like. A particularly advantageous material for sheathing I5 is a polyvinyl chloride sheet sold as Tu- Tuf by Sto-Cote Products, Inc. of Chicago, Ill. Tu Tuf is a laminated sheet formed by binding the faces of two extruded films together with the grain of one sheet at a right angle to the grain of the other sheet. To install sheathing 15, a rectangular web of the proper dimensions is draped over the generally semi-cylindrical skeletonframe 14. The lower edges are rolled under and around tube b on one side and tube Ilb on the other side as illustrated in FIG. 13 with respect to rail I0. Bicycle type clamps 40 (C-shaped in cross-section) are pressed over the end of the web and tubes 10b and llb at longitudinally spaced points along the rails I0 and II to secure sheathing l5 thereto.

If rails l0 and II are to be disposed on the ground a side panel 16 is not required. However, rails 10 and Il may be supported above the ground and a vertically disposed sheathing panel 16 provided as shown in FIG. I. The upper edge of sheathing 16 may be secured to rail 10 or 11 by rolling its edge over tube 10a or Ila and pressing bicycle type clamps 40a thereover as shown in FIG. I3 at longitudinally spaced points along rail I0 or 11.

The open end of a skeleton-frame 14 may be closed with a hanging panel 17 as shown in FIG. 1. Bicycle type clamps 40 may be used to secure sheathing 17 to rod F in the same way as sheathing 16 is secured to tube 100.

A water-proofjoint may be provided at the end of the shelter by clamping the end of the sheathing at spaced points to rod C and panel 17 to rod F as shown in FIG. 14.

One means for securing a sheathing 15 of one modular unit and the sheathing I5 of another modular unit when two skeleton-frames 14 are connected together in tandem is illustrated in FIG. 15. The sheathing 15 over one skeleton-frame I4 is rolled around rod F of a second skeleton-frame l4 and clamped thereto with bicycle type clamps 40.

In an alternate embodiment in which each skeletonframe [4 has rod C but does not have a rod F. sheathing 15 of one unit is rolled over and clamped with spaced bicycle clamps 40 to rod C ofthe other unit and sheathing I5 of the second unit is passed under rod C of its unit and around rod C of the other unit and secured by bicycle type clamp 40 thereto.

The corners at one end or on one side of the shelter may be pivotally secured to skids 45 as shown in FIG. [7 and the shelter towed from one location to another. Ordinary skids or small wheels may be used.

The distance longitudinally between the point on one side rail where an arched rod is attached and the point on the other side rail where the opposite end of the rod is attached may be varied. The greater this distance in relation to a given width between rails the more crossover points, the shorter the segments between crossover points and the greater the strength and stability of the structure. In one embodiment, the second rod A from the left shown in FIG. 18 is attached to rail I0 at a point which is longitudinally spaced from a first end of rail I0. The remaining rods A are then equally spaced along rail I0 with the last rod A being spaced a distance from the second end equal to the distance between the first end of rail 10 and second rod A. The spacing between the rods A will be about twice the distance between the second and last rods A and the adjacent ends of rail 10. Rods B are similarly spaced along rail 11. In a structure having a span of 20 feet between rails 10 and II with rods about 29 feet long spaced 3 feet apart along the rail and with that end of rod A attached to rail 11 spaced about nine feet longitudinally from the point where rod A is attached to rail 10, there are five cross-over points along each intermediate rod A and B. The resulting structure is much stronger than one covering the same area but having only six feet spacing between the ends of a rod and three feet spacing between rods. In order to complete the network of the embodiment of FIG. 18, the first rod A has one end attached to rail 11 but if it continued in its normal path it would cross rod C and extend beyond the end of rail 10. As shown in FIG. 18 this rod A is bent at the point it intersects rod C and is attached to rail 10 alongside the second rod A. The first rod B is similarly bent and attached to rail 11. Rods A and B of similar configuration are used at the opposite ends of rails 10 and 11. As shown in FIG. I8, a longitudinally extending ridge pole or rib may be disposed across and clamped to the rods A and B at approximately the midpoint of the generally semi-cylindrical skeleton-frame.

Clamps of the type illustrated in the drawing represent preferred means for fastening the rods together but other types of clamps may be used. For example, rods A and B may be fastened together by forcing a generally U-shaped clamp having a slot with bulges therein designed to fit about rods A and B just below or above a cross-over point. Such a clamp will resemble a clothes pin. The ends of rods A. B, C, D, E and F may be secured to the side rails by any suitable means. For example, an elongated slot greater in length than the sum of the diameter of the rods may be cut in the upper surface of tube or 11a. The ends of the rods are bent into an L-shape and inserted through the slot with the bent portion lying adjacent the inner wall of the tube. A wedge may then be driven between two adjacent rods to hold them in place. The sheathing may be sewn about the side rails or end rods of the structure or spaced eyelets may be used to secure it to the skeleton frame. Sewing. however. has the disadvantage that it is more difficult to remove the sheathing when the shelter is disassembled.

A skeleton-frame with the rods A and B clamped together at their cross-over points has the advantage that it will respond as a unit to absorb the energy of an applied load or force. A shelter having such a frame is capable of surviving winds of high velocity without substantial damage to the skeleton-frame. Moreover. the pattern of the support provided by the skeleton-frame for the sheathing minimizes tearing and other damage to thin plastic films or other material having a relatively low tear resistance. The skeleton-frame structure is very light in weight. For example. the arched portion of the embodiment of FIG. 1 made with 7/16 inch rods A and B weighs about one-half pound per square foot of area covered.

Although the invention has been described in detail for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that those skilled in the art can make variations therein without departing from the spirit and scope of the invention except as it may be limited by the claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A generally semi-cylindrically shaped skeletonframe for a shelter comprising a pair of laterally spaced side rails, means for maintaining the side rails in substantially equally spaced relationship throughout their length, a first series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail, a second series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail. the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail a distance which is substantially equal to the spacing between the opposite ends of the rods of the first series but in a direction opposite to the direction of spacing between the ends of the rods of the first series whereby a rod of one series crosses at least two rods of the other series, the spacing between rods of the second series being substantially] equal to the spacing between the rods of the first series, the length of all of said rods being substantially equal and greater than the spacing between the side rails whereby the said rods are substantially arcuate shaped and under tension and support all of any load on the frame above the side rails and transfer the load to the side rails, and means for securing rods together adjacent to a cross-over point whereby the segments of each rod between cross-over points is deflected from its normal path and is under compression and tension.

2. The skeleton-frame of claim 1 wherein the means for securing the rods together adjacent to cross-over points is a pair of bands with one band bent about one rod and the other bent around another rod near a crossover point of the two rods with the four ends of the two bands overlapping each other between the rods, the

length of the bands being greater than the distance around a rod plus one-half of the space between the rods whereby the ends of the band cannot be drawn together into contact with each other between the rods. and means for removably securing the four ends of the two bands together in spaced relationship with each other between the rods.

3. The skeleton-frame of claim I wherein the side rails are a pair of tubes disposed one over the other in spaced relationship secured together by longitudinally spaced webbings.

4. A shelter having the skeleton-frame of claim 3 and a sheathing thereover.

5. The skeleton-frame of claim 3 wherein the means for maintaining the spaced relationship between the side rail comprises an end rail spanning the space at one end of the side rails and means for securing the end rail to each side rail.

6. A shelter having the skeleton-frame of claim 5 and a sheathing thereover.

7. The skeleton-frame of claim 5 wherein the end rail is a tube with a portion at each end thereof lying in a plane which is substantially perpendicular to the longitudinal axis of the remainder ofthe tube, a hole extends through each of said end portions, a hole extends through one of the tubes of each side rail, a sleeve having longitudinally spaced holes therethrough is disposed over each end portion and over a portion of a side rail, and means is disposed in aligned holes in the sleeve, end rail and tube of the side rail to secure the end rail and side rails together.

8. A shelter having the skeleton-frame of claim 7 and a sheathing thereover.

9. A shelter having the skeleton-frame of claim 1 supported in spaced relationship above the ground and a sheathing panel hung from each side rail.

10. The shelter of claim 9 having at least one end closed with a sheathing panel hung from the said end rod.

11. The skeleton-frame of claim I wherein reinforcing means is provided between the side rails and arched rods.

12. The skeleton-frame of claim 1 wherein the spacing between the rods of the first series and the spacing between the rods of the second series are such that a pair of adjacent rods of one series and a pair of rods of the second series which cross the said adjacent rods enclose a space which is substantially that of a parallelogram having two acute and two oblique angles and said rods because they have been tensioned against compression prior to installation would normally tend to deflect from a plane crossing the points of attachment of the rod to the side rails but are secured together at cross-over points whereby tensions are created in the frame which tend to resist compression or deflection under weight applied to the skeleton-frame.

13. A shelter having a substantially semi-cylindrically shaped skeleton-frame comprising a pair of laterally spaced side rails, means for maintaining the side rails in substantially equally spaced relationship throughout their length, a first series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail, a second series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail a distance which is substantially equal to the spacing between the opposite ends of the rods of the first series but in a direction opposite to the direction of spacing between the ends of the rods of the first series whereby a rod of one series crosses at least two rods of the other series, the spacing between rods of the second series being substantially equal to the spacing between the rods of the first series. the length of all of said rods being sub stantially equal and greater than the spacing between the side rails whereby the said rods are arched and under tension and support all of any load on the frame above the side rails and transfer the load to the side rails, means for securing rods together adjacent to a cross-over point whereby the segment of each rod be tween cross-over points is deflected from its normal path and is under compression and tension, and a sheathing disposed over said skeletomframe.

14. A shelter comprising at least two generally semicylindrically shaped modular skeleton-frames in tandem, each skeleton-frame comprising a pair of laterally spaced side rails, means for maintaining the side rails in substantially equally spaced relationship throughout their length, a first series of longitudinally substantially, equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail, a second series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail a distance which is substantially equal to the spacing between the ends of the rods of the first series but in a direction opposite to the direction of spacing between the ends of the rods of the first series whereby a rod of one series crosses at least two rods of the other series, the spacing between rods of the second series being substantially equal to the spacing between the rods of the first series, the length of all of said rods being substantially equal and greater than the lateral distance between the side rails whereby the said rods are arched and under tension and support all of any load on the frame above the side rails and transfer the load to the side rails, means for securing abutting ends of the skeletonframes together whereby the segment of each rod between crossover points is deflected from its normal path and is under compression and tension, and a sheathing over the generally semi-cylindrical surface provided by the frame.

15. The shelter of claim 14 wherein each skeletonframe has a rod at each end thereof having a first end attached to one side rail and a second end attached to the other side rail at a point directly opposite the point where the first rod is attached, the said end rods are clamped together and the sheathing over the first skele ton-frame is secured to the end rod of the second skeleton-frame and the sheathing of the second skeleton frame is secured to the end rod of the first skeletonframe.

]6. A generally semi-cylindrically shaped skeletonframe for a shelter comprising a pair of laterally spaced side rails. means for maintaining the side rails in substantially equally spaced relationship throughout their length, a first series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail. a second series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail a distance which is substantially equal to the spacing between the ends of the rods of the first series but in a direction opposite to the direction of spacing between the ends of the rods of the first series whereby a rod of one series crosses at least two rods of the other series, the spacing between rods of the second series being substantially equal to the spacing between the rods of the first series, the length of all of said rods being substantially equal and greater than the spacing between the side rails whereby the said rods are arched, means for attaching the rods together at each cross-over point whereby the segment of each rod between cross-over points is deflected from its normal path and is under compression and tension, and at least one arched spring steel rod spanning the side rails and having its ends attached to the two rails at points substantially directly opposite each other. said spring steel rods supporting all of any load on the frame above the side rails and transferring the load to the side rails.

17. The skeleton-frame of claim 16 wherein said rods are secured together at cross-over points to form nominal parallelograms with the segments of the rods forming the parallelogram being deflected from their normal path and striving to return to the path thereby creating and using compressive forces and tension in the segments which is combined with stresses created by applied weight and other forces and such compressive forces on one parallelogram are transmitted to the network of parallelograms because a deflected rod of one parallelogram is also deflected in the adjacent parallelogram and combine to resist distortion from wind or other applied external forces; the resistance of the network increasing as the length of segments forming the parallelograms is decreased and the number of crosspoints along the rod is increased.

18. The skeleton-frame of claim 16 wherein the said rod which is attached to the side rails at points substantially opposite each other is at an end of the skeletonframe. 

1. A generally semi-cylindrically shaped skeleton-frame for a shelter comprising a pair of laterally spaced side rails, means for maintaining the side rails in substantially equally spaced relationship throughout their length, a first series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail, a second series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail a distance which is substantially equal to the spacing between the opposite ends of the rods of the first series but in a direction opposite to the direction of spacing between the ends of the rods of the first series whereby a rod of one series crosses at least two rods of the other series, the spacing between rods of the second series being substantially1 equal to the spacing between the rods of the first series, the length of all of said rods being substantially equal and greater than the spacing between the side rails whereby the said rods are substantially arcuate shaped and under tension and support all of any load on the frame above the side rails and transfer the load to the side rails, and means for securing rods together adjacent to a cross-over point whereby the segments of each rod between cross-over points is deflected from its normal path and is under compression and tension.
 2. The skeleton-frame of claim 1 wherein the means for securing the rods together adjacent to cross-over points is a pair of bands with one band bent about one rod and the other bent around another rod near a cross-over point of the two rods with the four ends of the two bands overlapping each other between the rods, the length of the bands being greater than the distance around a rod plus one-half of the space between the rods whereby the ends of the band cannot be drawn together into contact with each other between the rods, and means for removably securing the four ends of the two bands together in spaced relationship with each other between the rods.
 3. The skeleton-frame of claim 1 wherein the side rails are a pair of tubes disposed one over the other in spaced relationship secured together by longitudinally spaced webbings.
 4. A shelter having the skeleton-frame of claim 3 and a sheathing thereover.
 5. The skeleton-frame of claim 3 wherein the means for maintaining the spaced relationship between the side rail comprises an end rail spanning the space at one end of the side rails and means for securing the end rail to each side rail.
 6. A shelter having the skeleton-frame of claim 5 and a sheathing thereover.
 7. The skeleton-frame of claim 5 wherein the end rail is a tube with a portion at each end thereof lying in a plane which is substantially perpendicular to the longitudinal axis of the remainder of the tube, a hole extends through each of said end portions, a hole extends through one of the tubes of each side rail, a sleeve having longitudinally spaced holes therethrough is disposed over each end portion and over a portion of a side rail, and means is disposed in aligned holes in the sleeve, end rail and tube of the side rail to secure the end rail and side rails together.
 8. A shelter having the skeleton-frame of claim 7 and a sheathing thereover.
 9. A shelter having the skeleton-frame of claim 1 supported in spaced relationship above the ground and a sheathing panel hung from each side rail.
 10. The shelter of claim 9 having at least one end closed with a sheathing panel hung from the said end rod.
 11. The skeleton-frame of claim 1 wherein reinforcing means is provided between the side rails and arched rods.
 12. The skeleton-frame of claim 1 wherein the spacing between the rods of the first series and the spacing between the rods of the second series are such that a pair of adjacent rods of one series and a pair of rods of the second series which cross the said adjacent rods enclose a space which is substantially that of a parallelogram having two acute and two oblique angles and said rods because they have been tensioned against compression prior to installation would normally tend to deflect from a plane crossing the points of attachment of the rod to the side rails but are secured togeTher at cross-over points whereby tensions are created in the frame which tend to resist compression or deflection under weight applied to the skeleton-frame.
 13. A shelter having a substantially semi-cylindrically shaped skeleton-frame comprising a pair of laterally spaced side rails, means for maintaining the side rails in substantially equally spaced relationship throughout their length, a first series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail, a second series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail a distance which is substantially equal to the spacing between the opposite ends of the rods of the first series but in a direction opposite to the direction of spacing between the ends of the rods of the first series whereby a rod of one series crosses at least two rods of the other series, the spacing between rods of the second series being substantially equal to the spacing between the rods of the first series, the length of all of said rods being substantially equal and greater than the spacing between the side rails whereby the said rods are arched and under tension and support all of any load on the frame above the side rails and transfer the load to the side rails, means for securing rods together adjacent to a cross-over point whereby the segment of each rod between cross-over points is deflected from its normal path and is under compression and tension, and a sheathing disposed over said skeleton-frame.
 14. A shelter comprising at least two generally semi-cylindrically shaped modular skeleton-frames in tandem, each skeleton-frame comprising a pair of laterally spaced side rails, means for maintaining the side rails in substantially equally spaced relationship throughout their length, a first series of longitudinally substantially, equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail, a second series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail a distance which is substantially equal to the spacing between the ends of the rods of the first series but in a direction opposite to the direction of spacing between the ends of the rods of the first series whereby a rod of one series crosses at least two rods of the other series, the spacing between rods of the second series being substantially equal to the spacing between the rods of the first series, the length of all of said rods being substantially equal and greater than the lateral distance between the side rails whereby the said rods are arched and under tension and support all of any load on the frame above the side rails and transfer the load to the side rails, means for securing abutting ends of the skeletonframes together whereby the segment of each rod between cross-over points is deflected from its normal path and is under compression and tension, and a sheathing over the generally semi-cylindrical surface provided by the frame.
 15. The shelter of claim 14 wherein each skeleton-frame has a rOd at each end thereof having a first end attached to one side rail and a second end attached to the other side rail at a point directly opposite the point where the first rod is attached, the said end rods are clamped together and the sheathing over the first skeleton-frame is secured to the end rod of the second skeleton-frame and the sheathing of the second skeleton-frame is secured to the end rod of the first skeleton-frame.
 16. A generally semi-cylindrically shaped skeleton-frame for a shelter comprising a pair of laterally spaced side rails, means for maintaining the side rails in substantially equally spaced relationship throughout their length, a first series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail, a second series of longitudinally substantially equally spaced substantially parallel spring steel rods attached at one end to one side rail and at the other end to the other side rail, the point of attachment of one end of a rod to a side rail being spaced longitudinally from the point of attachment of the other end of the rod to the other side rail a distance which is substantially equal to the spacing between the ends of the rods of the first series but in a direction opposite to the direction of spacing between the ends of the rods of the first series whereby a rod of one series crosses at least two rods of the other series, the spacing between rods of the second series being substantially equal to the spacing between the rods of the first series, the length of all of said rods being substantially equal and greater than the spacing between the side rails whereby the said rods are arched, means for attaching the rods together at each cross-over point whereby the segment of each rod between cross-over points is deflected from its normal path and is under compression and tension, and at least one arched spring steel rod spanning the side rails and having its ends attached to the two rails at points substantially directly opposite each other, said spring steel rods supporting all of any load on the frame above the side rails and transferring the load to the side rails.
 17. The skeleton-frame of claim 16 wherein said rods are secured together at cross-over points to form nominal parallelograms with the segments of the rods forming the parallelogram being deflected from their normal path and striving to return to the path thereby creating and using compressive forces and tension in the segments which is combined with stresses created by applied weight and other forces and such compressive forces on one parallelogram are transmitted to the network of parallelograms because a deflected rod of one parallelogram is also deflected in the adjacent parallelogram and combine to resist distortion from wind or other applied external forces; the resistance of the network increasing as the length of segments forming the parallelograms is decreased and the number of cross-points along the rod is increased.
 18. The skeleton-frame of claim 16 wherein the said rod which is attached to the side rails at points substantially opposite each other is at an end of the skeleton-frame. 